The Non Uniform Memory Access (NUMA) network architecture used in a server network produces unpredictable memory access time in the server network. In the NUMA architecture, each server (node) has its own set of memories controlled by that server. Other nodes (servers) can access the memory via the RDMA (Remote DMA) access with permission from the owner (server) of the memory. The access route needs to go through a memory access controller (scheduler) under the control of the owner server, resulting in non-uniform memory access time and bandwidth. Furthermore, if the owner server fails, all memory accesses to its associated set of memories are blocked.
For an example, a NUMA network using Intel QPI (Quick Path Interconnect) presents significant degradation of memory access bandwidth when a server accesses the memory owned by other servers. In some instances, the memory bandwidth can be degraded by as much as 60% when a server accesses the memory owned by its next neighboring server, and by 80% when the server needs to accesses the memory owned by a server that is next to the next neighboring server (so called “one-removed).